CVE-2026-54721

HIGHPre-NVD 8.88.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This high-severity CVE scores 8.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.7% (53rd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 8.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Silverstripe UserForms provides a visual form builder for the Silverstripe CMS. From 6.0.0 until 6.4.9, 7.0.7, and 7.1.1, the userform email recipient subject field in the CMS accepts a specially crafted payload that can be interpreted as executable server-side code. An authenticated CMS user with permission to configure a UserForms email recipient can use the subject field to run arbitrary code on the server, compromising confidentiality, integrity, and availability. This issue is fixed in versions 6.4.9, 7.0.7, and 7.1.1.

CVSS v3
8.8
EG Score
8.8HIGHmedium confidence
EG Risk
40
EG Risk 40/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity88% × 45%
The EG Score, 8.8 of 10.
Exploitation0.7% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.7%
EPSS %ILE
53rd
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 27, 2026

Last Modified

September 9, 2026

Advisory Details (8)

Auto-updated Aug 27, 2026
Patch available. Sources: github_commit, github_pr, github_release, github.
GitHub advisoryMentions a patch (unverified)

Remote code execution via userforms email subject · Advisory · silverstripe/silverstripe-userforms · GitHub

https://github.com/silverstripe/silverstripe-userforms/security/advisories/GHSA-g8wr-r2v2-vqc6
GitHub release Patch Available

7.1.1

Patch available: silverstripe/silverstripe-userforms 7.1.1

https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.1.1
GitHub release Patch Available

7.0.7

Patch available: silverstripe/silverstripe-userforms 7.0.7

https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.0.7
GitHub release Patch Available

6.4.9

Patch available: silverstripe/silverstripe-userforms 6.4.9

https://github.com/silverstripe/silverstripe-userforms/releases/tag/6.4.9
GitHub pull request Patch Available

[CVE-2026-54721] Prevent RCE via email recipient subject

Patch available: silverstripe/silverstripe-userforms 6.4.9 (PR #1442 merged 2026-06-24)

https://github.com/silverstripe/silverstripe-userforms/pull/1442
GitHub pull request Patch Available

[CVE-2026-54721] Prevent RCE via email recipient subject

Patch available: silverstripe/silverstripe-userforms 7.0.7 (PR #1441 merged 2026-06-24)

https://github.com/silverstripe/silverstripe-userforms/pull/1441
GitHub commit Patch Available

commit c55494ad7c71 (silverstripe/silverstripe-userforms)

Patch available: silverstripe/silverstripe-userforms 6.4.9 (contains commit c55494ad7c71)

https://github.com/silverstripe/silverstripe-userforms/commit/c55494ad7c717b199a3c1663b43a54db5d95604c
GitHub commit Patch Available

commit 23c069866900 (silverstripe/silverstripe-userforms)

Patch available: silverstripe/silverstripe-userforms 7.0.7 (contains commit 23c069866900)

https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702

Vendor Advisories for CVE-2026-54721(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFix by version rangeDependents
silverstripe/userforms7.1.0
  • every version up to 6.4.9: fixed in 6.4.9
  • 7.0.0 up to 7.0.7: fixed in 7.0.7
  • 7.1.0 up to 7.1.1: fixed in 7.1.1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 56× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  3. 2026-10-12 15:56 UTCEG score recompute
  4. 2026-10-11 19:39 UTCEG score recompute
  5. 2026-10-11 16:54 UTCEG score recompute
  6. 2026-10-11 14:17 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  9. 2026-10-10 01:52 UTCEG score recompute
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  11. 2026-10-09 03:03 UTCEG score recompute
  12. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  13. 2026-10-08 01:18 UTCEG score recompute
  14. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  15. 2026-10-06 19:45 UTCEG score recompute
  16. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  17. 2026-10-06 07:32 UTCEG score recompute
  18. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  19. 2026-10-05 03:56 UTCEG score recompute
  20. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  21. 2026-10-03 15:13 UTCEG score recompute
  22. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  23. 2026-10-02 21:31 UTCEG score recompute
  24. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  25. 2026-10-01 20:45 UTCEG score recompute
Show 65 more
  1. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  2. 2026-09-30 19:54 UTCEG score recompute
  3. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  4. 2026-09-30 04:58 UTCEG score recompute
  5. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  6. 2026-09-29 12:16 UTCEG score recompute
  7. 2026-09-28 21:14 UTCEG score recompute
  8. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  9. 2026-09-27 19:07 UTCEG score recompute
  10. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  11. 2026-09-26 18:42 UTCEG score recompute
  12. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  13. 2026-09-24 16:48 UTCEG score recompute
  14. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  15. 2026-09-24 04:19 UTCEG score recompute
  16. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  17. 2026-09-22 15:37 UTCEG score recompute
  18. 2026-09-22 03:24 UTCEG score recompute
  19. 2026-09-21 02:56 UTCEG score recompute
  20. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  21. 2026-09-20 02:27 UTCEG score recompute
  22. 2026-09-19 01:43 UTCEG score recompute
  23. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  24. 2026-09-18 01:18 UTCEG score recompute
  25. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  26. 2026-09-17 00:31 UTCEG score recompute
  27. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  28. 2026-09-16 12:18 UTCEG score recompute
  29. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  30. 2026-09-15 11:51 UTCEG score recompute
  31. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  32. 2026-09-13 22:57 UTCEG score recompute
  33. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  34. 2026-09-12 22:32 UTCEG score recompute
  35. 2026-09-11 22:07 UTCEG score recompute
  36. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  37. 2026-09-11 09:54 UTCEG score recompute
  38. 2026-09-10 21:41 UTCEG score recompute
  39. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  40. 2026-09-09 00:40 UTCEG score recompute
  41. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  42. 2026-09-08 03:19 UTCEG score recompute
  43. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  44. 2026-09-07 01:09 UTCEG score recompute
  45. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  46. 2026-09-06 00:42 UTCEG score recompute
  47. 2026-09-05 00:14 UTCEG score recompute
  48. 2026-09-04 12:01 UTCEG score recompute
  49. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  50. 2026-09-02 22:58 UTCEG score recompute
  51. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  52. 2026-09-01 22:29 UTCEG score recompute
  53. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  54. 2026-09-01 10:16 UTCEG score recompute
  55. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  56. 2026-08-30 21:37 UTCEG score recompute
  57. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  58. 2026-08-30 09:24 UTCEG score recompute
  59. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  60. 2026-08-29 08:57 UTCEG score recompute
  61. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  62. 2026-08-28 20:43 UTCEG score recompute
  63. 2026-08-28 19:47 UTCEG score recompute
  64. 2026-08-27 20:27 UTCEG score recompute
  65. 2026-08-27 17:23 UTCEG score recomputeFirst assessed: 8.8 HIGH

Related CVEs(same product + same CWE)

Same product

1 shown

Packagist:silverstripe/userforms

Frequently asked(5)

What is CVE-2026-54721?
CVE-2026-54721 is a high-severity vulnerability; its CVE record was published on August 27, 2026. Silverstripe UserForms provides a visual form builder for the Silverstripe CMS. From 6.0.0 until 6.4.9, 7.0.7, and 7.1.1, the userform email recipient subject field in the CMS accepts a specially crafted payload that can be interpreted as executable server-side code. An authenticated CMS user with…
When was the CVE record for CVE-2026-54721 published?
The CVE record for CVE-2026-54721 was published on August 27, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-54721 actively exploited?
CVE-2026-54721 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (53rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-54721?
CVE-2026-54721 has a CVSS base score of 8.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-54721?
A fix for CVE-2026-54721 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-54721 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-54721

Explore →

Is Your Infrastructure Affected by CVE-2026-54721?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs